11/13/13 AIM: How was fingerprinting developed in forensic science? DO NOW: Are fingerprints individual or class evidence? EXPLAIN YOUR ANSWER. HOMEWORK:

11/13/13

• AIM: How was fingerprinting developed in forensic science?

• DO NOW: Are fingerprints individual or class evidence? EXPLAIN YOUR ANSWER.

• HOMEWORK: Textbook read 72-73 and 76-77(Anatomy of a fingerprint). What are friction ridges and where are they found?

DactyloscopyThe study of fingerprints

Historically William Herschel—required Indians to put their fingerprints on

contracts, and also as a means of identifying prisoners Henry Faulds—claimed that fingerprints did not change over

time and that they could be classified for identification Alphonse Bertillon—proposed body measurements as a

means of identification; termed anthropometry Francis Galton—developed a primary classification scheme

based on loops, arches and whorls. Edward Richard Henry—in collaboration with Galton instituted

a numerical classification system Juan Vucetich—developed a fingerprint classification based on

Galton’s that is used in Spanish-speaking countries

William and Will west

Fingerprinting

Recording or Making Prints rolling inked prints primary identification number

Lifting Prints Black, white and fluorescent powder Chemicals—ninhydrin, iodine, silver nitrate, cyanoacrylate

Other Types of Prints Palm, lip, teeth, eye, ear, voice, shoe and footprints

What is a fingerprint?

• Skin has an outer layer (epidermis) which has ridges projecting inward, and an inner layer (dermis) which has projections pressing into the spaces between ridges

• A fingerprint is a pattern made by the friction ridges, which is left behind due to sweat and oil that sticks to them.

• Fingerprints form during the fetal stage of development.

http://www.smithsonianmag.com/video/Where-Do-Fingerprints-Come-From.html

When do they form?

• In early embryonic development & remain constant

What determines fingerprints?

• DNA - Genes• & environmental

forces: pressures within the womb and contact with the amniotic fluid

Formation of fingerprints• Skin layer growth

– 3-4 month– Middle layer of skin buckles and folds

creating the first ridges

• Creation of ridges– fetus touches surrounding structures, exact

position in the womb and the density of the womb's amniotic fluid determine how every individual ridge will form

• Ridge patterns: 6 months– The ridges on a fetus's fingertips have

formed three main patterns categorized as arches, loops and whorls

• Fingerprint characteristics– two common characteristics found in every

fingerprint: ridge end and bifurcation– The sequences of ridge end and bifurcation

characteristics are different in every fingerprint

11

Anatomy of Fingerprints• Epidermis

– Outer layer of the skin• Dermis

– Inner layer of the skin• Dermal papillae

– Layer of cells between the epidermis and dermis

– Responsible for determining the form and pattern of the ridges on the surface of the skin

Fundamental Principlesof Fingerprints

A fingerprint is an individual

characteristic.

A fingerprint will remain

unchanged during an

individual’s lifetime.

Fingerprints have general

characteristic ridge patterns

that permit them to be

systematically classified.

Thursday 11/14/13

• AIM: How are imprints individual pieces of evidence?

• DO NOW: Explain how fingerprints are formed• HOMEWORK: Textbook read pages 79-80.

Answer questions 6-10 on page 100• Wednesday hw: Textbook read 72-73 and 76-

77(Anatomy of a fingerprint). What are friction ridges and where are they found?

DONOW ANSWER

• DNA controls formation of epidermis and dermis

• The pressure on the amniotic fluid finalizes the ridge pattern

Fingerprint Ridges

• Give skin traction for picking up items.• The fine lines curve, circle, and arch.• Valleys - grooves or furrows • Hills - friction ridges

Fingerprint principle 1• A fingerprint is an individual characteristic • no two fingers have yet been found to posses

identical ridge characteristics

Principle 2

• Fingerprints have general ridge patterns that permit them to be systematically classified

Fingerprint Pattern• Pores on the ridges• Discharge perspiration

from the sweat glands• Sweat mixed with oil

can leave a latent invisible fingerprint

Other Prints

Ears—shape, length and width

Voice—electronic pulses measured on a

spectrograph

Foot—size of foot and toes; friction ridges on the foot

Shoes—can be compared and identified by type of

shoe, brand, size, year of purchase, and wear pattern.

Kendall/Hunt Publishing Company 19

Other Prints

Palm—friction ridges can be identified and may be used against suspects.

Chapter 4

Other Prints

Footprints are taken at birth as a means of identification of infants.

Chapter 4

Other Prints

Lips—display several common patterns

Short vertical lines Short horizontal lines Crosshatching Branching grooves

Chapter 4

Other Prints

Teeth—bite marks are unique and can be used to identify suspects. These imprints were placed in gum and could be matched to crime scene evidence.

Chapter 4

Other Prints

The blood vessel patterns in the eye may be unique to individuals. They are used today for various security purposes.

Chapter 4

Friday 11/15/13

AIM: how are fingerprints identified? DO NOW: List the three major

characteristics used to identify fingerprints. Explain why each of your ten fingerprints

are different.

Chapter 4

Characteristics of fingerprints

Chapter 4

Arch

An arch has friction ridges that enter on one side of the finger and cross to the other side while rising upward in the middle.

Types Plain- the arch is mild Tented- the arch is

spiked upward

Plain arch

Tented arch

Loop

A loop must have one or more ridges entering and exiting from the same side it began.

Loops must have one delta (a“Y” pattern from diverging ridges)

Types Radial--opens toward the thumb Ulnar--opens toward the “pinky” (little

finger)

Which type of loop is this, if on the right hand? Left hand?deltaΔ

Whorl

A Whorl has a minimum of 2 deltas.

Types Plain- 2 symmetric deltas and a

complete ridge circuit (circular in pattern)

Central Pocket- 2 asymmetric deltas, one side appears to be stretched

Double Loop- 2 loops and 2 deltas Accidental- a whorl that does not fit

the 3 above pattern types

31 Plain whorl

Central Pocket Whorl

32

Double Loop (whorl)

33

Accidental whorl

34

http://on.aol.com/video/how-to-

determine-fingerprint-patterns-72416331


• White lines in ridge patterns represent diet pattern.

• Many white lines indicate celiac disease

36

Determining fetal environment

• The more symmetrical your fingerprints the more stable the amniotic environment


Monday 11/18/13

• AIM: how are fingerprints analyzed?• DO NOW: 1- What are the 3 general fingerprint

patterns?2-Explain the roll of the delta in fingerprint identificationHOMEWORK: Using the class information, create a bar graph of the % of fingerprint patterns2- Do the classroom % match the national average?


Loops• Must have one

delta

40

Whorls: 2 deltas

Arches NO deltas

Human population fingerprint distribution

• Loops: 65%• Whorls: 30%• Arches: 5%

FINGERPRINT IDENTIFICATIONFINGERPRINT IDENTIFICATION

Table 4.2 Frequency of fingerprints Loops WhorlsArchesUlnar radial plain other plain tented60% 5% 20% 10% 4% 1% loops = 65% whorl=30% arches =5%


On your computer paper

Thumb Index Middle Ring Pinky

Right Hand

Ridge pattern

LeftHand

Ridge pattern

Thursday 11/21/13

• AIM: how are fingerprints compared?HOMEWORK:Textbook pg 100 questions 3-10. write out the question followed by the answer

Identify each fingerprint pattern.

?A B

CD E

Right Hand

Left Hand

Left Hand

Right Hand

Right Hand

49

Fingerprint Identification

• The uniqueness of a fingerprint can be determined by the pattern of ridges and valleys as well as the minutiae points.

• Minutiae points are local ridge characteristics that occur at either a ridge bifurcation or a ridge ending.

50

Ridge Characteristics

Minutiae—characteristics of ridge patterns

Ridge ending Short ridge Dot or fragment Bifurcation Double bifurcation Trifurcation Bridge Island Enclosure Spur

Kendall/Hunt Publishing Company

RIDGE CHARACTERISTICS (Minutiae) RIDGE CHARACTERISTICS (Minutiae)

COMMONCOMMON OCCASIONALOCCASIONAL RARERARE

Ending RidgeEnding Ridge

Bifurcation or fork

Bifurcation or fork

DotDot

Eye or EnclosureEye or Enclosure

“T” Junction“T” Junction

Short RidgeShort Ridge

TrifurcationTrifurcation

Ridge CrossingRidge Crossing

Row of DotsRow of Dots

52

Fingerprint Basics (minutiae)

Bifurcation Ridge ending

dotDouble bifurcation

53


Opposed bifurcation

Island (short ridge)

Hook (spur) Lake (enclosure)

54


Ridge crossing

trifurcation

Opposed bifurcation/ridge ending)

Bridge

RIDGE CHARACTERISTICS MAGNIFIEDRIDGE CHARACTERISTICS MAGNIFIED

Points 1, 2, 4, 5 are Ending RidgesPoints 1, 2, 4, 5 are Ending Ridges

Points 8, 10, 11 are BifurcationsPoints 8, 10, 11 are Bifurcations

Point 7 Short RidgePoint 7 Short Ridge

Points 3 and 9 are DotsPoints 3 and 9 are Dots

Point 6 is an Enclosure (ISLAND)Point 6 is an Enclosure (ISLAND)

11

22

44

55

88

10101111

99

77

33

66


Fingerprint Minutiae

How are fingerprints compared?How are fingerprints compared?

A. Fingerprints are compared by noting the ridge pattern on two prints to determine whether or not they match.

B. The minutiae characteristics are then compared

C. An identification is established when a number of these characteristics occupy the same relative position on the two prints.

A. Fingerprints are compared by noting the ridge pattern on two prints to determine whether or not they match.

B. The minutiae characteristics are then compared

C. An identification is established when a number of these characteristics occupy the same relative position on the two prints.


Comparison

There are no legal requirements in the United States on the number of points. Generally, criminal courts will accept 8 to 12 points of similarity.

Activity: Sticky Fingers

Modern Fingerprint Analysis

Computer system stores patterns and minutiae of prints

AFIS: automated fingerprint identification system

Fingerprints


Henry Classification system• Developed a method of classifying fingerprints. • modified by the FBI that allowed all set of 10

fingerprints in the world to be divided into 1024 groups.


Henry Classification system• Developed a method of classifying fingerprints. • modified by the FBI that allowed all set of 10

fingerprints in the world to be divided into 1024 groups.



Primary Classification

The Henry—FBI ClassificationEach finger is given a point value

right left


Primary Classification

Assign the number of points for each finger that has a whorl and substitute into the equation:

right right left left left index ring thumb middle little + 1

right right right left left thumb middle little index ring +1

That number is your primary classification number

=

ArchesArches are the simplest type of fingerprints that are formed by ridges that enter on one side of the print and exit on the other. No deltas are present.

Plain ArchRidges enter on one side and

exit on the other side.

Tented Arches Similar to the plain arch,

but has a spike in the center.

Spike or “tent”

LoopsLoops must have one delta and one or more ridges that enter and leave on the same side. These patterns are named for their positions related to the radius and ulna bones.

Delta

Ulnar Loop (Right Thumb)

Loop opens toward right or the ulna bone.

Radial Loop (Right Thumb)

Loop opens toward the left or the radial bone.

NOTE: On the left hand, a loop that opens to the left would be an ulnar loop, while one that opens to the right would be a radial loop.

WhorlsWhorls have at least one ridge that makes (or tends to make) a complete circuit. They also have at least two deltas. If a print has more than two deltas, it is most likely an accidental.

Draw a line between the two deltas in the plain and central pocket whorls. If some of the curved ridges touch the line, it is a plain whorl. If none of the center core touches the line, it is a central pocket whorl.

Plain Whorl

Central Pocket Whorl

Whorls – Part 2

Accidental Whorl

Accidental whorls contain two or more patterns (not including the plain arch), or does not clearly fall under any of the other categories.

Double Loop Whorl

Double loop whorls are made up of any two loops combined into one print.

Delta

Delta

WHAT IS A FINGERPRINT?WHAT IS A FINGERPRINT?

A fingerprint is a pattern comprised of ridges and valleys.

A Ridge – is a high.

A Valley – is a depression or low.

A fingerprint is a pattern comprised of ridges and valleys.

A Ridge – is a high.

A Valley – is a depression or low.

Friction ridges are also found on our palms, feet and toes.Friction ridges are also found on our palms, feet and toes.

ValleyRidge

Anatomy of fingerprints

• Finger touches a surface–Perspiration–Oils from hairy portions of the body

–Transferred onto surface• Leaves fingerprint

70

71

What is a Fingerprint?

• Skin has an outer layer (epidermis) which has ridges projecting inward, and an inner layer (dermis) which has projections pressing into the spaces between ridges

• A fingerprint is a pattern made by the friction ridges, which is left behind due to sweat and oil that sticks to them.

• Fingerprints form during the fetal stage of development.

There are 3 types of fingerprints

1. Visible – left by dirt, grease, blood, etc. Does not need processing


2. Impression – indentation in soft material (butter, putty, tar, etc.)

Does not need processing


3. Latent – requires processing to make visible and suitable for analysis

What are the invisible components?

Multiple sweat glands secrete onto fingers, palms, etc.

Sweat contains:

Inorganic ions (Na+, Cl -) Proteins, amino acids

Lipids Other

76

Lifting Latent Prints

Developing a print requires chemicals that react with secretions that cause the print to stand out against its background. It may be necessary to attempt more than one technique, done in a particular order so as not to destroy the print.

Powders--adhere to both water and fatty deposits. Choose a color to contrast the

background. Iodine--fumes react with oils and fats to produce a

temporary yellow brown reaction.

Physical Development: Dusting

Apply powder to latent print or area.

Powder adheres to print.

Brush and Powder

Physical Development: Dusting

Apply powder to latent print or area.

Powder adheres to print.

Magnetic Brush

and Powder

79

Lifting Latent Prints (cont)

Ninhydrin--reacts with amino acids to produce a purple reaction.

Silver nitrate--react with chlorides to form silver chloride, a material which turns gray when exposed to light.

Cyanoacrylate--”super glue” fumes react with water and other fingerprint constituents to form a hard,

whitish deposit. In modern labs and criminal investigations, lasers and alternative

light sources are used to view latent fingerprints. It was first used by the FBI in 1978. Since lasers can damage the retina of the eye, special precautions must be taken and a filter used.

Chemical Development:

1. Silver Nitrate

No longer used (messy, not sensitive) Silver reacts with Cl - ions in print


2. Iodine Fuming Iodine sublimes

(solid → gas) Iodine reacts with lipid

components; becomes trapped in the print.

Fuming wand or chamber

Dirty Brown Color

Fingerprints > Analysis

82

Iodine Fingerprint


3. Ninhydrin Reacts with amino acids; purple color Painted or sprayed on area Heated to react

84

Ninhydrin Fingerprint


4. Super glue fuming Fumes with heat or base (NaOH) Fumed in cabinets Off-white print

86

Cyanoacrylate Fingerprints


Ninhydrin and super glue prints can be further processed:

Dusted Chemically treated to

fluoresce (using laser or alternative light)

11/13/13 AIM: How was fingerprinting developed in forensic science? DO NOW: Are fingerprints individual or class evidence? EXPLAIN YOUR ANSWER. HOMEWORK:

Documents

skin slide

fingerprint ridges

classified slide

constant slide

ridge pattern slide

amniotic fluid slide

fingerprint classification

fingerprint principle